Hi Moritz, No I mean to process in parallel the stats over many vector entities for example areas. Immagine a large raster with many polygons that want to know the mean or max value in the area.
Ciao, Lorenzo 2018-06-14 13:20 GMT+02:00 Stefan Blumentrath <[email protected]>: > Yes, access to attributes would be a challenge / bottleneck for > parallelisation, esp. if you have many areas in your vector map. Note that > not only SQLite but also DBF is still supported (which puts some > limitations)... > > Please note also: https://trac.osgeo.org/grass/ticket/3523 for some > suggestions for speeding up v.rast.stats (without parallelisation). > Once multiple raster map input is supported, statistics could be computed > in parallel for each raster map and then finally uploaded to the attribute > table in one single process... > Yet, the region adjustment performed by v.rast.stats would then have to be > handled differently from current solution... > > I would say it is worth a ticket... > > If you want a text file, you could use r.univar directly, no? > > Cheers > Stefan > > -----Original Message----- > From: grass-dev <[email protected]> On Behalf Of Moritz > Lennert > Sent: torsdag 14. juni 2018 13:05 > To: Lorenzo Bottaccioli <[email protected]>; GRASS developers > list <[email protected]> > Subject: Re: [GRASS-dev] v.rast.stats parallel process > > On 14/06/18 12:24, Lorenzo Bottaccioli wrote: > > Hi all, > > > > There is any chance that the v.rast.stats will be paralellized? > > You mean to treat several rasters at the same time ? > > It shouldn't be too complicated to write a wrapper script for this. I > would imagine the biggest problem to be the handling of the access to the > attribute database file. Not sure that you can have concurrent access to > this file by several parallel processes. If this is an issue, we would > probably have to add the option to output v.rast.stats results to text > files and then load content of these files into at the attribute table of > the vector map at the end... > > Moritz > _______________________________________________ > grass-dev mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/grass-dev >
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